lttng-sessiond/channel.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License as published by the Free
   6  * Software Foundation; only version 2 of the License.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  15  * Place - Suite 330, Boston, MA  02111-1307, USA.
  16  */
  17
  18 #define _GNU_SOURCE
  19 #include <string.h>
  20 #include <unistd.h>
  21
  22 #include <lttng/lttng.h>
  23 #include <lttng-ht.h>
  24 #include <lttng-sessiond-comm.h>
  25 #include <lttngerr.h>
  26
  27 #include "channel.h"
  28 #include "kernel.h"
  29 #include "ust-ctl.h"
  30 #include "utils.h"
  31 #include "ust-app.h"
  32
  33 /*
  34  * Return allocated channel attributes.
  35  */
  36 struct lttng_channel *channel_new_default_attr(int dom)
  37 {
  38         struct lttng_channel *chan;
  39
  40         chan = zmalloc(sizeof(struct lttng_channel));
  41         if (chan == NULL) {
  42                 PERROR("zmalloc channel init");
  43                 goto error_alloc;
  44         }
  45
  46         if (snprintf(chan->name, sizeof(chan->name), "%s",
  47                                 DEFAULT_CHANNEL_NAME) < 0) {
  48                 PERROR("snprintf default channel name");
  49                 goto error;
  50         }
  51
  52         chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
  53         chan->attr.switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
  54         chan->attr.read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
  55
  56         switch (dom) {
  57         case LTTNG_DOMAIN_KERNEL:
  58                 chan->attr.subbuf_size = DEFAULT_KERNEL_CHANNEL_SUBBUF_SIZE;
  59                 chan->attr.num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
  60                 chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
  61                 break;
  62         case LTTNG_DOMAIN_UST:
  63         case LTTNG_DOMAIN_UST_PID:
  64                 chan->attr.subbuf_size = DEFAULT_UST_CHANNEL_SUBBUF_SIZE;
  65                 chan->attr.num_subbuf = DEFAULT_UST_CHANNEL_SUBBUF_NUM;
  66                 chan->attr.output = DEFAULT_UST_CHANNEL_OUTPUT;
  67                 break;
  68         default:
  69                 goto error;     /* Not implemented */
  70         }
  71
  72         return chan;
  73
  74 error:
  75         free(chan);
  76 error_alloc:
  77         return NULL;
  78 }
  79
  80 /*
  81  * Disable kernel channel of the kernel session.
  82  */
  83 int channel_kernel_disable(struct ltt_kernel_session *ksession,
  84                 char *channel_name)
  85 {
  86         int ret;
  87         struct ltt_kernel_channel *kchan;
  88
  89         kchan = trace_kernel_get_channel_by_name(channel_name, ksession);
  90         if (kchan == NULL) {
  91                 ret = LTTCOMM_KERN_CHAN_NOT_FOUND;
  92                 goto error;
  93         } else if (kchan->enabled == 1) {
  94                 ret = kernel_disable_channel(kchan);
  95                 if (ret < 0 && ret != -EEXIST) {
  96                         ret = LTTCOMM_KERN_CHAN_DISABLE_FAIL;
  97                         goto error;
  98                 }
  99         }
 100
 101         ret = LTTCOMM_OK;
 102
 103 error:
 104         return ret;
 105 }
 106
 107 /*
 108  * Enable kernel channel of the kernel session.
 109  */
 110 int channel_kernel_enable(struct ltt_kernel_session *ksession,
 111                 struct ltt_kernel_channel *kchan)
 112 {
 113         int ret;
 114
 115         if (kchan->enabled == 0) {
 116                 ret = kernel_enable_channel(kchan);
 117                 if (ret < 0) {
 118                         ret = LTTCOMM_KERN_CHAN_ENABLE_FAIL;
 119                         goto error;
 120                 }
 121         }
 122
 123         ret = LTTCOMM_OK;
 124
 125 error:
 126         return ret;
 127 }
 128
 129 /*
 130  * Create kernel channel of the kernel session and notify kernel thread.
 131  */
 132 int channel_kernel_create(struct ltt_kernel_session *ksession,
 133                 struct lttng_channel *attr, int kernel_pipe)
 134 {
 135         int ret;
 136         struct lttng_channel *defattr = NULL;
 137
 138         /* Creating channel attributes if needed */
 139         if (attr == NULL) {
 140                 defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL);
 141                 if (defattr == NULL) {
 142                         ret = LTTCOMM_FATAL;
 143                         goto error;
 144                 }
 145                 attr = defattr;
 146         }
 147
 148         /* Channel not found, creating it */
 149         ret = kernel_create_channel(ksession, attr, ksession->trace_path);
 150         if (ret < 0) {
 151                 ret = LTTCOMM_KERN_CHAN_FAIL;
 152                 goto error;
 153         }
 154
 155         /* Notify kernel thread that there is a new channel */
 156         ret = notify_thread_pipe(kernel_pipe);
 157         if (ret < 0) {
 158                 ret = LTTCOMM_FATAL;
 159                 goto error;
 160         }
 161
 162         ret = LTTCOMM_OK;
 163 error:
 164         free(defattr);
 165         return ret;
 166 }
 167
 168 /*
 169  * Enable UST channel for session and domain.
 170  */
 171 int channel_ust_enable(struct ltt_ust_session *usess, int domain,
 172                 struct ltt_ust_channel *uchan)
 173 {
 174         int ret = LTTCOMM_OK;
 175
 176         /* If already enabled, everything is OK */
 177         if (uchan->enabled) {
 178                 DBG3("Channel %s already enabled. Skipping", uchan->name);
 179                 goto end;
 180         }
 181
 182         switch (domain) {
 183         case LTTNG_DOMAIN_UST:
 184                 DBG2("Channel %s being enabled in UST global domain", uchan->name);
 185                 /* Enable channel for global domain */
 186                 ret = ust_app_enable_channel_glb(usess, uchan);
 187                 break;
 188         case LTTNG_DOMAIN_UST_PID:
 189         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 190         case LTTNG_DOMAIN_UST_EXEC_NAME:
 191                 ret = LTTCOMM_NOT_IMPLEMENTED;
 192                 goto error;
 193         }
 194
 195         if (ret < 0) {
 196                 if (ret != -EEXIST) {
 197                         ret = LTTCOMM_UST_CHAN_ENABLE_FAIL;
 198                         goto error;
 199                 } else {
 200                         ret = LTTCOMM_OK;
 201                 }
 202         }
 203
 204         uchan->enabled = 1;
 205         DBG2("Channel %s enabled successfully", uchan->name);
 206
 207 end:
 208 error:
 209         return ret;
 210 }
 211
 212 /*
 213  * Create UST channel for session and domain.
 214  */
 215 int channel_ust_create(struct ltt_ust_session *usess, int domain,
 216                 struct lttng_channel *attr)
 217 {
 218         int ret = LTTCOMM_OK;
 219         struct lttng_ht *chan_ht;
 220         struct ltt_ust_channel *uchan = NULL;
 221         struct lttng_channel *defattr = NULL;
 222
 223         /* Creating channel attributes if needed */
 224         if (attr == NULL) {
 225                 defattr = channel_new_default_attr(domain);
 226                 if (defattr == NULL) {
 227                         ret = LTTCOMM_FATAL;
 228                         goto error;
 229                 }
 230                 attr = defattr;
 231         }
 232
 233         /* Create UST channel */
 234         uchan = trace_ust_create_channel(attr, usess->pathname);
 235         if (uchan == NULL) {
 236                 ret = LTTCOMM_FATAL;
 237                 goto error;
 238         }
 239
 240         switch (domain) {
 241         case LTTNG_DOMAIN_UST:
 242                 DBG2("Channel %s being created in UST global domain", uchan->name);
 243                 chan_ht = usess->domain_global.channels;
 244
 245                 /* Enable channel for global domain */
 246                 ret = ust_app_create_channel_glb(usess, uchan);
 247                 break;
 248         case LTTNG_DOMAIN_UST_PID:
 249         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 250         case LTTNG_DOMAIN_UST_EXEC_NAME:
 251         default:
 252                 ret = LTTCOMM_NOT_IMPLEMENTED;
 253                 goto error_free_chan;
 254         }
 255
 256         if (ret < 0 && ret != -EEXIST) {
 257                 ret = LTTCOMM_UST_CHAN_ENABLE_FAIL;
 258                 goto error_free_chan;
 259         }
 260
 261         uchan->enabled = 1;
 262         lttng_ht_add_unique_str(chan_ht, &uchan->node);
 263         DBG2("Channel %s created successfully", uchan->name);
 264
 265         free(defattr);
 266         return LTTCOMM_OK;
 267
 268 error_free_chan:
 269         /*
 270          * No need to remove the channel from the hash table because at this point
 271          * it was not added hence the direct call and no call_rcu().
 272          */
 273         trace_ust_destroy_channel(uchan);
 274 error:
 275         free(defattr);
 276         return ret;
 277 }
 278
 279 /*
 280  * Disable UST channel for session and domain.
 281  */
 282 int channel_ust_disable(struct ltt_ust_session *usess, int domain,
 283                 struct ltt_ust_channel *uchan)
 284 {
 285         int ret = LTTCOMM_OK;
 286
 287         /* Already disabled */
 288         if (uchan->enabled == 0) {
 289                 DBG2("Channel UST %s already disabled", uchan->name);
 290                 goto end;
 291         }
 292
 293         /* Get the right channel's hashtable */
 294         switch (domain) {
 295         case LTTNG_DOMAIN_UST:
 296                 DBG2("Channel %s being disabled in UST global domain", uchan->name);
 297                 /* Disable channel for global domain */
 298                 ret = ust_app_disable_channel_glb(usess, uchan);
 299                 break;
 300         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 301         case LTTNG_DOMAIN_UST_EXEC_NAME:
 302         case LTTNG_DOMAIN_UST_PID:
 303                 ret = LTTCOMM_NOT_IMPLEMENTED;
 304                 goto error;
 305         }
 306
 307         if (ret < 0 && ret != -EEXIST) {
 308                 ret = LTTCOMM_UST_DISABLE_FAIL;
 309                 goto error;
 310         }
 311
 312         uchan->enabled = 0;
 313
 314         DBG2("Channel %s disabled successfully", uchan->name);
 315
 316         return LTTCOMM_OK;
 317
 318 end:
 319 error:
 320         return ret;
 321 }